The present invention relates to a control system, and in particular to a control system for a motor vehicle.
Control systems for motor vehicles command various actuators of the motor vehicles to perform certain tasks. Examples of control systems include traction control systems, anti-lock braking systems and stability control systems. Each of these control systems has a particular function that is carried out when certain information is sensed by the vehicle. For example, the anti-lock braking system will prevent the tires of the vehicle from locking during braking. Furthermore, vehicle control systems coordinate some or all of the actuators of the vehicle to produce a desired vehicle movement or procedure.
Heretofore, total control structures for motor vehicles have included coordinating elements which convert a command from a higher hierarchical level into commands for elements of a lower hierarchical level. The contents of the commands, which are transmitted from above to below in the hierarchical structure, define physical variables that determine the interfaces between the individual hierarchical levels. The command flow is only from a higher hierarchical level to a lower hierarchical level. U.S. Pat. Nos. 5,351,776 and 6,154,688 disclose control systems wherein the command flows only from the higher hierarchical level to the lower hierarchical level. However, the aforementioned control systems do not revise their commands to the lower hierarchical levels when the actuators being commanded by the lower hierarchical levels cannot carry out the commands.
Accordingly, an apparatus solving the aforementioned disadvantages and having the aforementioned advantages is desired.